Update onchain.c

[roconnor-blockstream]

Round tx fees up.

Fixes #1194 (comment) ... maybe. I didn't even try compiling this. I just directly edited it in github.

[ZmnSCPxj]

ACK 806bc02

[jb55]

this is begging for tests ;)

[ZmnSCPxj]

Looking more deeply, maybe it is incomplete? wallet/wallet.c also contains fee calculation code.

lightning/wallet/wallet.c

Line 289 in 044705a

*fee_estimate = weight * feerate_per_kw / 1000;

[roconnor-blockstream]

Good catch in wallet.c

Sorry, this PR wasn't entirely serious.

[roconnor-blockstream]

Actually, while I think these are all errors, Perhaps they are not causing the problems in #1194. Since feerate_per_kw should be exactly 4000, the division should be exact here.

Strike the above. The feereate_per_kw should be 250 (and itself another possible problem due to rounding)

[roconnor-blockstream]

Superseded by #1251